A spray booth is a structure that provides a ventilated, air filtered and temperature controlled environment in which spraying activities such as painting and powder coating can take place. A spray booth is necessary for the safe execution of such activities, since the sprayed materials include solvents and particulate material that must not enter the atmosphere in large quantities. The particulate material that does not stick to the article being sprayed must be removed from the spraying area to ensure safe working conditions, and to manage environmental impact.
A spray booth also provides a controlled supply of filtered air that aids the spraying process and leads to higher quality finishes. In addition, it is necessary to heat sprayed materials in order to dry them (in a process known as baking), and the spray booth provides a controlled temperature environment in which such baking can be undertaken.
By way of example and explanation, one typical automotive spray booth is illustrated in FIGS. 1 and 2 of the accompanying drawings. The spray booth 1 comprises a roof portion 10 from which two pairs 12, 14 and 13, 15 of side portions extend to the ground, thereby forming a closed chamber in which spraying can be carried out. One or more of the side portions is movable to allow an object, in this case a car 3, to be located in the chamber for spraying.
A plenum 16 is formed adjacent the roof 10 by the provision of a filter element 18 substantially parallel to, and spaced from the inner surface of the roof portion. The filter element 18 may extend across the whole of the roof portion 10, as illustrated, or may be provided across only a limited area. As will be described in more detail below, an input air flow 20 is supplied into the plenum 16, after which it passes through the filter 18 and forms an incoming air flow 22. Ideally the air flow 22 is uniform across the width of the booth.
The airflow 22 passes around the object 3, and forms an outgoing air flow 24. This outgoing airflow 24 passes through an outgoing filter 26, into an extraction area 28, and into an extraction duct 30 which provides an extracted airflow 32. The extraction area 28 is provided below the object 3 being sprayed, and typically extends below the ground surface of the location of the spray booth 1.
The input airflow is provided by air handling equipment, such as that shown for illustrative purposes in FIG. 3 of the accompanying drawings. The air handling equipment 40 of FIG. 3 comprises input ducting 44 which guides air 42 into the equipment from the atmosphere. A fan unit 46 is provided for drawing in the air 42, and for moving the air via ducting 47 to a heater 48 which operates to heat the air to a desired temperature. The temperature controlled air 20 is then provided to the spray booth via ducting 49.
Air extraction from the booth 1 is provided by air extraction equipment, such as that shown for illustrative purposes in FIG. 4 of the accompanying drawings. The extracted airflow 32 is drawn through ducting 50 by an extraction fan unit 52. The airflow passes through a further filtration unit 54 before exiting to atmosphere 58 via further ducting 56.
The spray booth 1 of FIGS. 1 and 2 and the air handling equipment of FIGS. 3 and 4 has been described by way of example and illustration only, and it will be readily appreciated that the design and construction of a spray booth can vary. For example, the input and output air handling equipment can be combined to reduce the number of fan units and reduce the heating requirements by using recirculation of air.
It will also be appreciated that the principles of the spray booth described above can be applied to a booth of any scale for enabling spraying of objects of any size. For example, one spray booth could be provided for the spraying of small components, whilst another could be provided for the spraying of aircraft, or wind turbine towers. Naturally, the specific design requirements of each application will determine the size and specification of the spray booth and the equipment, but the principles remain the same as for the automotive booth described above.
In the automotive sector, a body shop which repairs and repaints cars and other vehicles, may have the need for several spray booths to enable multiple jobs to be carried out at any one time. However, it has been recognised that the movement of vehicles in such a body shop can lead to increased work times, and so body shops are starting to use workshop bays for multiple tasks, only one of which is repainting. For example, a damaged vehicle may be driven into the workshop and positioned in a repair bay in which a range of actions will be carried out on the vehicle. Damaged mechanical parts may be replaced, and damaged bodywork repaired or replaced. Once this repair work has been carried out, the vehicle must then be transferred to the spray booth for finishing. In order to reduce the number of vehicle movement in the workshop, each work area can be equipped as a spray booth, so that, in effect, all repair work is carried out in the controlled environment provided by the booth. However, such a solution is expensive, both in terms of capital cost, and in terms of running costs. Since not all actions require the provision of a controlled environment, such costs are unnecessary.
Accordingly, it is desirable to provide a solution that reduces the number of vehicle movements in the workshop, whilst providing the required controlled environments for spraying and finishing at a reasonable cost.